This invention relates to providing laminated sheets of thermoplastic, or thermoplastic sheets of multi-layered construction.
In the manufacture of various products, it becomes highly desirable to utilize multiple-layered thermoplastic sheets, of laminated construction. For example, there are various articles of manufacture, wherein it becomes highly desirable to utilize layers having different characteristics. Specifically, in the manufacture of plastic cups, it may be desirable to utilize a thermoplastic material having high impact strength, such as butadiene-styrene. However, such a material generally has a dull, matte finish which does not have the attractive appeal associated with other types of thermoplastics, such as crystal polystyrene, which may have a high gloss finish. Accordingly, it may be desirable to utilize one type of material for strength or structural characteristics, and another for its aesthetic characteristics. Even further, it may be desirable to utilize various types of thermoplastics, laminated together, for various applications, with one laminate or layer providing strength in one direction, another providing strength in another direction, and with an intermediate layer perhaps providing bulk, and with outer layers being pre-selected according to aesthetic characteristics of materials which comprise the outer layers, for example. It will be noted that these instances in terms of product possibilities are merely suggested for purposes of example, it being understood that this invention encompasses the lamination or multi-layer construction of various types of materials, of various numbers of layers, for covering a myriad of uses.
In the past, multiple-layered thermoplastic layers, or laminates have been constructed, but generally such involves the use of a plurality of sheet extruders, for laminating one sheet to another subsequent to the extrusion of each sheet, by using various co-extrusion processes having complex dies and other apparatus. Often, such apparatus is considerably expensive.